Device for positioning a fabric on a sewing machine for the purpose of producing pleats of a desired depth and spaced at desired intervals

Abstract: Device (1) comprises: a support plate (2) that can be connected to sewing machine (30) in a predetermined position with respect to working line (K) of the needle; two sliders (7a, 8a) which are free to slide with respect to said plate (2) on opposite sides of said working line (K) and are equipped with positioning markers (15, 16) which slide integrally with respective sliders (7a, 8a) along two bars (20, 21), marked in millimeters; one (7a) of the sliders is equipped with means for securing fabric (33) that is to be worked, and means are present for locking slides (7, 8) and corresponding sliders (7a, 8a) in the desired working positions. By correctly positioning sliders (7a, 8a) as reference points for the task to be carried out, pleats are obtained that have exactly the desired depths and spacing, with considerable savings of time.

Description: The present invention pertains to the area of products made of fabric, and more specifically to the subarea thereof that relates to the production of fabrics that are supposed to feature pleats, generally evenly spaced, e.g., parts of drapes or fabrics with pleats of various types. At present, to perform operations of this type, before making the various machine stitches that fix the pleats in place, workers in this branch of industry are obliged first to do an extensive amount of (manual) work subdividing, measuring, and marking or tacking the pleats; this entails a considerable loss of time, which is reflected in the costs of the finished product. In addition, without fixed reference points it is difficult to make the manual measurements sufficiently precise, with the result that, once the work is completed, the spaced between the various pleats and the depths of said pleats wind up varying slightly from pleat to pleat. Some examples of the prior art are provided with features that give some reference points and improve under a certain extent the accuracy of work, but do not offer the results required by a work that has to be carried out inside an industrial system as far as the repeatibility and the absolute precision are concerned. For example Doc. US-A-2 966 126 discloses a device which apparently is similar to that of the present application, but which doesn't foresee any means apt to positively securing the fabric to the device same, therefore the precision of work is not assured. Documents CH-A-642 412 and EP-A-475 913 describe two devices that are suitable only for effecting very particular works such as fixing support means (hooks or the like) on fabrics with pleats, and that require, to this purpose, the installation of further devices on a sewing machine, capable of moving the fabric on a direction transversal with respect to the direction of the usual sewing line. The inventor of the object of the present invention has provided a solution to the above-mentioned problems by creating a device that makes it possible, once the desired pleat depth and space between two successive pleats have been determined, to make the pleats themselves based on precise references, which consist of component parts of the device; said components need to be positioned only one, at the beginning of the task. More particularly, the device that is the object of the invention makes it possible to precisely position a piece of fabric on a sewing machine in order to produce on it pleats of a predetermined depth that are spaced at desired intervals; said device comprises, like the prior art examples, a support plate, two sliders, two or more bars marked in millimeters, as well as means suitable for locking said sliders in a desired position, but is characterized by the characterizing section of claim 1. A more detailed description of the device and the method of employing it will now be given, making refecence to the attached drawings, where: Fig. 1 shows a diagrammatic view of the essential parts of a preferred embodiment of the device of the invention; Fig. 2 shows a front view; Fig. 3 shows a schematic of how the fabric is positioned on the device in order to produce successive pleats; Fig. 4 shows a diagrammatic view of the device with a shaped cover mounted thereon. According to the preferred embodiment depicted in Figs. 1 and 2, device 1 is composed of a support plate 2 (in this specific case, it is L-shaped), one part of which supports the functional parts of the device, while the other part serves the purpose of securing device 1 itself on a sewing machine 30 in a predetermined position with respect to working line K of the needle. This area is depicted schematically in the figures. The above-mentioned securing is accomplished by, e.g., providing two or more holes 3, 4 for attaching as many clamping screws 5, 6 which, penetrating plate 2, are screwed into threaded holes that are normally already present on sewing machine 30 since they are used to attach various accessories. In the event that such holes are not present, however, it would not be difficult to drill new ones in the desired locations. Facing support plate 2 are two flat slides 7, 8 that are arranged parallel to longitudinal axis h of the plate itself, on opposite sides of working line K of the needle; each of said slides features a bar-shaped slider 7a, 8a that extends perpendicular to said axis. As will be seen below, said two sliders 7a, 8a serve as reference points and points for securing the piece of cloth to be worked. Said two slides 7, 8 are attached to plate 2 in such a way as to be able to slide with respect to said plate along above-mentioned axis h, and in the example shown this is accomplished by means of two pairs of parallel bars 11, 12, each pair of which is integral with one of the two slides, and the bars of which are spaced in such a way as to be able to slide without play in the above-mentioned direction along a guide bar 22 which is held between them and which is rigidly attached to support plate 2. The sliding of slides 7, 8 to achieve the desired positioning of respective sliders 7a, 8a is accomplished by turning two threaded bolts 9, 10 which are equipped with drive knobs 9a, 10a, which are connected to support plate 2, parallel to its longitudinal axis h, and which are free to rotate around the axis itself. The motion is transmitted to two slides 7, 8 by the fact that two above-mentioned threaded bolts 9, 10 mate with an equal number of small blocks 13, 14 which are integral with, respectively, said slides 7, 8; in each of said blocks is a threaded hole. On each slide 7, 8 is a positioning marker 15, 16 which moves integrally with respective slide 7, 8 and indicates its position, i.e., the sliding that occurs with respect to one of two reference bars 20, 21, marked in millimeters, which are integral with support plate 2 and are located close to each of said markers 15, 16. Once a fixed reference point that lies on working line K of the needle has been established, it is possible, by turning the drive knob, to cause slides 7, 8 and thus their sliders 7a, 8a to slide until they reach two positions that are a predetermined distance from the fixed reference point and face one another. The locking of two slides 7, 8 in the desired positions is accomplished by doing, e.g., the following: to support plate 2 are attached two screws 25, 26 that extend perpendicularly upward, and in each slide 7, 8 is a straight slot 31, 32 that is suitable for holding said screws 25, 26, with the latter also being parallel to longitudinal axis h of plate 2, i.e., ultimately with respect to the direction in which slides 7, 8 slide. When the slides have reached the respective desired positions, on each of screws 25, 26 a threaded knob 23, 24 is turned until it locks; on said screws are, respectively, two bushes 27, 28 that are located between said knobs 23, 24 and respective slides 7, 8; this ensures the locking of the latter. As will be clear from the description of the way in which the device is employed, it is necessary, in order for the work to be done carefully and precisely, that the fabric be kept motionless with respect to two sliders 7a, 8a as it is being worked. This can be accomplished by locking the fabric with respect to just one of the sliders, with the protruding edge being subsequently kept taut manually. In the example in question, this is accomplished by means of a rotating arm 17 which, being hinged to one slide 7, is mounted above corresponding slider 7a. In Fig. 3 fabric 33, which is inserted between arm 17 and slider 7a, is held therein by the preloading of a spring 19, Fig. 2, which is arranged coaxially with a threaded element 34 that is integral with slider 7a and passes through arm 17; this preloading is accomplished by screwing onto threaded element 34 a holding pawl 18 that varies the compression of spring 19 that is placed between said pawl and arm 17. It is possible to adjust said preloading as desired, depending on the thickness of the fabric and the holding pressure that the operator wishes to exert. A description will now be given of the way in which device 1 is used, making particular reference to Fig. 3. Once said device 1 is attached to sewing machine 30, the position of working line K of the needle is also fixed with respect to said device. Imagine that the operator wishes to make pleats "a" cm in depth (with a spread of "2a" cm with the pleat opened) that are "b" cm apart. Then, proceeding as explained, slider 7a, which is located further to the left and is equipped with a system for holding the fabric, is moved in such a way that the left edge of rotating arm 17 is positioned "b" cm to the left, starting from working line K of the needle, and the right edge of slider 8a, which is further to the right, is moved to a position "a" cm to the right, in the opposite direction with respect to said working line K. To position sliders 7a, 8a accurately, the positions of two markers 15, 16 are read on respective bars 20, 21, marked in millimeters, and the measurements indicated thereon indicate the lengths of the movements of two sliders 7a, 8a, as well as that of rotating arm 17, with respect to working line K of the needle; this is done simply by ensuring the accurate initial calibration of the markers with respect to the corresponding components. Slides 7, 8 and consequently sliders 7a, 8a are then locked by locking above-mentioned threaded knobs 23 and 24. Stitch 33a of the last pleat is disposed along the left edge of rotating arm 17 by, as mentioned, placing fabric 33, as mentioned between slider 7a and rotating arm 17 located above it; this exerts the desired clamping pressure, which is also facilitated by the stepwise thickening produced by stitch 33a itself. Fabric 33 is then placed under right-hand slider 8a and, with it held taut, a pleat is easily produced by turning it over the right edge of the latter and placing it on top of the part of the fabric that is being held taut by the lefthand slider. The stitching of the pleat is then done; by virtue of geometry alone, this stitch will have desired depth "a" and will be "b" cm from the previous pleat. The next operation is then carried out for all of the successive pleats, which will then all be uniform and evenly spaced. In experiments the savings of time achieved by using the device of the invention has been determined to be up to 80%, and the finished work exhibits a level of accuracy and precision never before encountered. To achieve even greater precision, the inventor has made provision for attaching to the ends of said markers 15, 16 (Fig. 4) a tool 27, 28, which is known per se and which is able, since it is marked in micrometers, to indicate any displacement of the marker attached to it along bar 20, 21, marked in millimeters, which is associated therewith. This makes it possible to control the sizes of the displacements to within ± 1/10 of a millimeter. It is evident that the shape, the arrangement, and the interconnection of the various components can be modified or switched and that equivalent solutions can be adopted within the framework of the concepts set forth in the attached claims. The example that is described and depicted should thus be construed as a preferred embodiment, without being either restrictive or limiting. In order to improve the appearance and functionality of the device, the inventor has also made provision for attaching a box-shaped cover 29, Fig. 4, on which are mounted above-mentioned bars 20, 21, marked in millimeters. Said cover 29 is of such a size and shape as to cover at least the part of support plate 2 on which the functional elements of the device are mounted and is equipped with slots and holes through which can pass two sliders 7a, 8a, two threaded bolts 9, 10 that are integral with the support plate, two markers 15, 16 that are integral with respective slides 7, 8, and two bushes 27, 28 that are attached around screws 25, 26 which extend from support plate 2. With device 1 assembled and with shaped cover 29 mounted on it, there thus protrude above the cover itself two sliders 7a, 8a, knobs 9a, 10a for driving threaded bolts 9, 10, knobs 23, 24 for locking slides 7, 8, and the ends of two above-mentioned markers 15, 16 which can thus be connected to above-mentioned tools 27, 28.

Claims: Device (1) that is able to ensure the exact positioning of a piece of fabric (33) on a sewing machine (30) for the purpose of producing on said fabric pleats that are of a predetermined depth and are spaced a desired distance apart, wherein said device comprises: a support plate (2) that is equipped with means (3, 4, 5, 6) of securing said fabric on said sewing machine (30) in a predetermined position with respect to working line (K) of the machine's needle; two sliders (7a, 8a) that are parallel to one another and essentially perpendicular to longitudinal axis (h) of said support plate (2), to which they are attached in such a way as to be able to slide parallel to said longitudianl axis (h) and on opposite side of said working line (K) of the needle, with each of said sliders (7a, 8a) having a marker (15, 16) that extends perpendicularly from it said sliders (7a, 8a) being parallel to the working line (K) of the needle, two or more bars (20, 21), marked in millimeters, which are integral with said support plate (2) and are arranged, parallel to above-mentioned longitudinal axis (h), near said markers (15, 16) of said sliders (7a, 8a); means (23, 25, 27 and 24, 26, 28) that are suitable for locking said two sliders (7a, 8a) in a desired position, characterized in that the device is also provided with means of attachment (17, 18, 19, 34) that are suitable for locking fabric (33) with respect to one (7a) of said sliders while the protruding edge of the fabric (33) same is kept taut. Device according to claim 1, comprising: a support plate (2) that has two or more holes (3, 4) for attaching clamping screws (5, 6) and two screws (25, 26) that extend perpendicular with respect to said plate; two flat slides (7, 8) that are arranged parallel to longitudinal axis (h) of said plate (2) on opposite sides of working line (K) of the needle of sewing machine (30), with each of said slides featuring a bar-shaped slider (7a, 8a) that extends in a direction perpendicular to said longitudinal axis (h), a marker (15, 16) that is perpendicular to the slides themselves, a pair of small bars (11, 12) that are parallel to one another, spaced a certain distance apart, and are arranged parallel to said longitudinal axis (h) of support plate (2), as well as a straight slot (31, 32) that is also parallel to said axis (h) and is able to mate with one of said screws (25, 26) which extend perpendicular to the support plate; a guide bar (22) which is integral with support plate (2) and is located between the small bars that form said pairs (11, 12) which are attached to slides (7, 8) in such a way that the small bars themselves are able to slide without play along said plate as a result of the motion of said slides (7, 8); two threaded bolts (9, 10) that are connected to support plate (2) parallel to said longitudinal axis (h) which are free to rotate around the axis itself and are equipped at their ends with drive knobs (9a, 10a); two bars (20, 21), marked in millimeters, which are integral with support plate (2) and are arranged parallel to plate longitudinal axis (h) close to said markers (15, 16) that are integral with said slides (7, 8); where each slide also has: a) a small block (13, 14) in which there is a threaded hole that is able to mate with one of said threaded bolts (9, 10); and with the locking of slides (7, 8) in a desired position being accomplished by attaching around each of said screws (25, 26) extending from support plate (2) a bush (27, 28) that is forced against slide (7, 8) associated with it by locking a threaded knob (23, 24) that is screwed to corresponding screw (25, 26). Device according to claim 2, also including a box-shaped cover (29) to which are attached said two bars (20, 21), marked in millimeters, with said cover being of such a size and shape as to cover at least the part of support plate (2) on which are mounted the functional elements of device (1) and having slots and holes through which can pass: two slides (7a, 8a); said two threaded bolts (9, 10) that are integral with support plate (2); said markers (15, 16) that are integral with slides (7, 8); two bushes (27, 28) that are attached around said screws (25, 26) extending from support plate (2); in such a way that, with the device assembled, the following are outside of the box-shaped cover: drive knobs (9a, 10a) of threaded bolts (9, 10); knobs (23, 24) for locking slides (7, 8); the ends of markers (15, 16). Device according to claim 3, in which at the ends of each of said two markers (15, 16) is a tool (27, 28) which, because it is marked in micrometers, is able to indicate any displacement of the marker itself along bar (20, 21), marked in millimeters, that is associated therewith. Device according to one of claims 2, 3, or 4, in which above one of sliders (7a) is a rotating arm (17) that is hinged to corresponding slide (7), which exerts on slider (7a) a pressure that is able to clamp fabric (33) while it is being worked, with said pressure being regulated by varying the preloading of a spring (19); said preloading is applied coaxially to a threaded element (34) which extends through both slider (7a) and arm (17), with said spring (19) being located between rotating arm (17) and a holding pawl (18) that is screwed onto threaded element (34).

Inventors: DE STEFANO VINCENZO, DE STEFANO, VINCENZO
Applicants: STEFANO VINCENZO DE, DE STEFANO, VINCENZO
Application year: 1994
Main classification: D05B35
IPC codes: D05B35